The invention relates generally to articulated joints used for prosthetic devices. More particularly, the invention relates to hip-joints for artificial legs.
Known hip-joints of the type under discussion include a fastening angle to be secured to a support on a human body and having a substantially horizontal shank and a substantially upright shank carrying the joint which is comprised of two joint members one of which is pivotable relative to the other so that the joint can take a position corresponding to the standing position of the artificial leg or a position corresponding to the sitting position of the artificial leg.
The above described hip-joints have been known and used for many years when it has been necessary to use a totally artificial leg. The fastening angle is usually connected to the support strapped about the base of the amputated leg. An elastic means between the first joint member and the second joint member has been usually employed in order to hold the artificial leg in the standing and sitting positions and provide for an optimal movement of the artificial upper shank.
The first joint element is usually applied to the substantially horizontal shank of the fastening angle in known hip-joint structures. The elastic means between the first joint member and the second joint member have been formed as elastic bands or strips which have been clamped between both joint members or between one of the members and the artificial leg.
Conventional prosthetic hip-joints have required relatively large space. This has caused certain cosmetic difficulties, particularly in the sitting position of a prosthesis carrier. The problem occurred because with conventional hip-joints in the sitting position of the user the joint is merely pushed out from the seat surface so that a comfortable sitting position is badly disturbed. Furthermore, conventional hip-joints are not optimal in handling.
There has been also known a prosthetic hip-joint provided with a lock which, however permits for only a very limited movement of the hip-joint during walking. Furthermore, a prosthesis carrier should have manually loosened the lock in order to take a sitting position. The lock had a locking function for the standing position. Such conventional hip-joints are not comparable with the hip-joints described herein above because they cause inconveniences for a user in that the manually operated lock must be always accessible. Furthermore, the function of the lock can be carried out in relatively new hip-joints by elastic bands.